Before you do anything you have to set your daily calorie budget. Don't know how that works? No worries, I have a calculator you can use to set your starting point.
Figuring out what to eat is hard. Gainslog makes it easy to swap foods around until you match your remaining macros.
Write down your progress. Add in some observations like "I ate too much", "I should eat more", "I lost my energy - should increase carbs".
They say we need to look in the past to improve the future. See how often you failed to reach your calories and what macronutrient were neglected - and improve upon that.